Blood Test May Detect Early Forms Of Cancer

The discovery of a protein that appears to be found in all types of tumors may lead to a simple blood test to screen for early cancers, according to a University of Tennessee biochemist.

The chief advantage of the test, which is being evaluated as a potential routine screening technique for use in doctors` offices and medical labs, is that it appears to be able to detect any kind of cancer, Dr. Edsel Bucovaz reported at the annual meeting of the American Chemical Society in Chicago.

In tests with more than 2,500 patients who had been diagnosed as having a wide variety of early stage cancers, the tumor marker, called B-protein, was 87 percent accurate in confirming the presence of the cancers, he said.

``B-protein detects cancer at an early stage of development,`` Bucovaz said. ``There is little doubt that treatment of cancer would have a better success record if cancer were detected at an earlier stage, when treatment is most successful,`` he said.

Among more than 4,500 people who did not have cancer, the test accurately produced negative results in 90 to 95 percent of the cases, said Bucovaz, who is with the university`s Center for Health Sciences.

``We don`t know exactly what B-protein is, but it is found in cancer patients, and the level of the protein increases as the cancer progresses,``

he said.

Researchers are trying to find out what role B-protein plays in cancer in the hopes that such information could lead to a better understanding of tumor development and possibly improved therapies, he said.

Linda Anderson, a spokeswoman for the National Cancer Institute, cautioned against being overly optimistic, because no accurate blood screening test for cancer has been developed.

``Dr. Bucovaz`s work will have to be rigorously and strictly evaluated to determine its efficacy as a screening test,`` she said.

Some monitoring tests for specific cancers already are in use. The best known of these is CEA, which is most commonly used to monitor the progress of patients with colon cancer. President Reagan, who recently underwent surgery for colon cancer, is being monitored with the CEA test, which detects another type of protein.

Despite missing some of the cancers and providing false positive results in a small number of cases, B-protein could serve as a highly effective, simple and inexpensive screening test, Bucovaz said. The test uses radioactive tracers to detect the presence of B-protein in blood serum.

Bucovaz said he has developed two forms of the test. The B-protein assay quick-test is designed to be used as a simple screening technique, and the B- protein assay is intended to confirm the results of the screening test and to monitor the progress of patients being treated for cancer.

Using the quick test, doctors could draw blood samples from patients in their offices and get results in minutes, Bucovaz said. Patients with positive findings would undergo clinical examinations to look for cancer, he said.

A positive finding in patients in whom no cancer is found after examination could alert a doctor to keep an eye on those patients and have them come in for regular check-ups, he said.

As a monitoring device the test can be used to follow the progress of cancer therapy, he said. As surgery, chemotherapy or radiation treatment brings the cancer under control, B-protein levels decrease, he explained.

Patients in remission would then undergo routine tests to check for rising levels of B-protein, which would indicate the cancer is flaring up again, Bucovaz said. Detecting recurrent cancers early also improves the chance that they can be treated successfully, he said.

Several companies are evaluating the test, but it may take two to three years before screening and monitoring tests are available, he said.